Key and Modulation

What harmonic features are involved when a musical passage, or a work, is in a particular key? How is balance achieved between modulations that reinforce the home key and those that supplant it altogether? The chapter starts by analyzing “Im wunderschönen Monat Mai,” the opening song in Robert Schumann’s song-cycle Dichterliebe. It considers the criteria for identifying keys and provides a brief history of the role of closure in the definition of key before discussing how composers move between keys and what kinds of key relations they choose. It then explores new theoretical insights on common-tone modulation, along with the issue of content versus cadence in determining degrees of certainty about the establishment of new internal keys. It also compares definitions of tonicization and modulation and concludes with an assessment of how key relations have been shaped into tonal spaces. An important observation—one that highlights the tension between contents and cadences—is that the presence or absence of a final cadence is commonly used to ascertain whether or not a key has been fully articulated. The chapter describes a range of scenarios of such tension as well as the views of various theorists and analysts regarding the relative importance of content versus cadence.